The present invention relates generally to log processing apparatus and in particular to veneer lathe charger apparatus which scans the log with a light beam to determine its optimum axis for greatest veneer production and positions such log so that such optimum axis is moved into alignment with the lathe axis.
One such lathe charger apparatus is shown in my earlier U.S. Pat. No. 4,197,888 by A. L. McGee et al issued Apr. 15, 1980. In this patented lathe charger apparatus the optimum axis of a log is determined by directing a light beam past the side of the log through the space between such log and a reference edge to project an image of such space onto a photoelectric detector while the log is rotated to thereby determine the optimum axis of such log. While a similar scanning technique is employed in the preferred embodiment of the present invention, it will be appreciated that any light beam scanning technique can be employed for determining the optimum axis of the log including light reflection from the side of the log, as shown in U.S. Pat. No. 3,852,579 of Sohn et al.
It has been found that prior lathe chargers employing separate horizontal positioning means and vertical positioning means for moving the charger spindles in horizontal and vertical directions, are complicated and expensive. In addition, in the past such horizontal and vertical positioners have been located beneath the log so that they are damaged when a log is accidentially dropped. Also, such prior lathe chargers scan the log to determine its optimum axis at the same position where such log is engaged by transfer arms and moved to the lathe axis. This necessitates reclamping of the log by the clamp arms used for rough centering, to hold it in position after scanning while the charger spindles are disengaged and the transfer arms are moved to engage the log. The log support and centering means in the present lathe charger returns from the scan position to the pick up position and does not reclamp the log in the transfer position. As a result the log is only held by the charger spindles when it is engaged by the transfer arms in the transfer position. No reclamping of the log is necessary because in the scanning position the charger spindles are spaced sufficiently below the transfer position to provide clearance for the transfer means as it moves back from the lathe axis positon to the transfer position. This enables four legs to be simultaneously acted upon by the lathe charger apparatus of the present invention and greatly increases the speed of operation of such charger. This reduces the speed of operation of the charger apparatus because reclamping prevents the clamp members from being used to support and roughly center the next log prior to scanning. These problems are overcome by the charger apparatus of the present invention.